g++ compile time calculations

["Wesley Smith" <wesley.hoke@xxxxxxxxx>]

Hi,
I'm trying to figure out how to do some compile time C++ template
programming.  I have something working that calculates the length of a
string, but I'm not sure how to evaluate what is actually being done
at compile time and what is being done at run time.  Here's is my
code:

template <class T>
class StringLength
{
	public:
		static int eval(T* a)
				{	return ((*a) == '\0') ? 0 : (StringLength<T>::eval(a+1) + 1);  }
};

template <class T>
inline int stringlength(T* a) { return StringLength<T>::eval(a); }



//in main somewhere
cout << stringlength<>("This is a string") << endl;


My GCC version is gcc version 4.0.1 (Apple Computer, Inc. build 5341).
I'm on OSX 10.4.8 on a PPC.   Basically, I'm trying to find out what
compiler output I can look at or somehow query things at runtime to
find out what did and didn't compile down.

thanks,
wes